Less Lake Ice, More Potential Lake Effect Snow

Nov 15, 2017

By Climate Central

Arctic air begins to race across the relatively milder water of the Great Lakes every fall, generating lake effect snow. These snowfalls can be intense, but are often localized. Several inches of snow can fall a few miles away from a place that only gets flurries. As the planet has warmed from the increase in greenhouse gases, so have the lakes, meaning more evaporation into the atmosphere during the winter. Paradoxically, this had led to an increase in lake effect snow, but that trend is not expected to last.

A recent study used a regional climate model to investigate these changes in lake effect snow if our current rate of greenhouse gas emissions continues. By mid-century, the amount of seasonal lake effect snow is projected to increase modestly, as the Great Lakes will remain ice-free longer into the winter. However, as the air warms, the amount of snow during the transitional seasons of late fall and early spring is expected to decrease, with more of the precipitation falling as rain.

By late century, the frequency of extreme cold over the Great Lakes is expected to decrease substantially. Similarly, lake temperatures are projected to increase further. This warming environment implies an increase in rain at the expense of snow during the winter. The largest decrease in snow comes during November, as temperatures in this early part of the season will be higher, also suggesting a later onset of the lake effect snow season.

Lake effect snow will still occur in a warming world, but by the late 21st century, we can expect a shortened lake effect snow season. Rather than peaking in fall and early winter, heavy lake effect snow would be pushed back later in the season, generally from January through March.

Methodology: Historical lake effect snow trends are from a station list compiled by Kunkel et al., 2009. Snow amounts in this week’s projections graphic reflect total snow in areas downstream of the individual Great Lakes. Full methodology is outlined in Notaro et al (2015).

Lake effect snow will still occur in a warming world, but by the late 21st century, we can expect a shortened lake effect snow season. Rather than peaking in fall and early winter, heavy lake effect snow would be pushed back later in the season, generally from January through March.

On the Great Lakes, the maximum ice cover this year is down substantially from 2014 and 2015, which were the 2nd and 4th highest percentages on record, respectively. Despite its large season-to-season variability, the maximum winter ice cover has been trending downward in recent decades. In addition to curtailing recreational activities such as

Snow is piling up in parts of western New York, Michigan, Pennsylvania and Ohio thanks to an incursion of Arctic air blowing over the unusually warm waters of the Great Lakes. Totals are expected to be between several inches to more than a foot, and more could be in store next week. The contrast between cold air and warm water fuels what is called

This week, parts of Oswego County in New York got a stunning 3 feet of lake effect snow. It was a rare event for a February and one that can be pinned to near “rock bottom” ice cover on the Great Lakes, as one scientist put it. Ice cover on the lakes stood at a mere 12 percent as of Feb. 11 (compared to 63 percent at the same time last year) thank